Spectrometer based on double-plane reflection grating

Abstract

The utility model discloses a spectrograph based on a double-plane reflection grating, and belongs to the technical field of spectrographs. The first plane reflection grating and the second plane reflection grating which are adjacently distributed are arranged in the spectrograph, light rays are subjected to secondary light splitting through the two plane reflection gratings, on the basis that the resolution of the spectrograph is guaranteed, a focusing lens with a large focal length does not need to be adopted, the overall size of the spectrograph is effectively reduced, the manufacturing cost is saved, and the cost is reduced. And the miniaturization design of the spectrograph is facilitated. In addition, the diffraction angle is increased by using the double reflection gratings, the problem that the diffraction angle of the near-infrared light for the high-scale density of the reflection gratings is small is solved, and the diffraction efficiency of the near-infrared light is improved.

Description

Technical Field

[0001] This application relates to the field of spectrometer technology, and in particular to a spectrometer based on a dual-plane reflection grating. Background Technology

[0002] A spectrometer is a precision optical instrument used to qualitatively and quantitatively analyze the molecular structure and chemical composition of substances by measuring their emission, transmission, or diffuse reflection absorption spectra. Spectrometers offer advantages such as ease of use, speed, non-destructive operation, and cleanliness, and are widely used in numerous fields including industry, agriculture, military, medicine, petrochemicals, aerospace, and environmental protection, making them one of the most important optical analytical instruments.

[0003] To improve spectral resolution, gratings require high-density scribe lines. However, to ensure diffraction efficiency, the number of grating lines is typically low in the near-infrared band, which limits spectral resolution. Increasing the focal length of the internal mirrors can improve spectrometer resolution; however, this results in a larger overall spectrometer size, hindering miniaturization design. Utility Model Content

[0004] This application provides a spectrometer based on a dual-plane reflection grating. It solves the problem of large size in existing spectrometers. The technical solution is as follows:

[0005] On the one hand, a spectrometer based on a dual-plane reflection grating is provided, the spectrometer comprising:

[0006] An entrance slit, a collimating lens, a first planar reflective grating, a second planar reflective grating, a focusing lens, and a detector assembly;

[0007] The entrance slit is used to emit a light beam;

[0008] The collimating lens is located on the light-emitting side of the entrance slit and is used to collimate the light beam and guide it to the first planar reflective grating.

[0009] The first planar reflective grating is used to split the beam, and the split beam is guided to the second planar reflective grating, which splits the beam a second time.

[0010] The focusing lens is used to focus the beam after secondary beam splitting and guide it to the photosensitive surface of the detector assembly.

[0011] Optionally, the scribe line density of the first planar reflective grating is less than that of the second planar reflective grating.

[0012] Optionally, the scribe line density of the first planar reflective grating ranges from 900 / mm to 1400 / mm; the scribe line density of the second planar reflective grating ranges from 900 / mm to 1400 / mm.

[0013] Optionally, the focusing lens is a lens group or a concave mirror.

[0014] Optionally, the spectrometer based on a dual-plane reflection grating further includes a plane mirror located on the light-emitting side of the focusing lens, the plane mirror being used to guide the light beam focused by the focusing lens to the photosensitive surface of the detector assembly.

[0015] Optionally, the detector assembly includes a detector and a cylindrical lens, the cylindrical lens being located between the photosensitive surface of the detector and the planar reflector, and the rear surface of the cylindrical lens being planar and parallel to the window glass of the detector.

[0016] The beneficial effects of the technical solutions provided in this application include at least the following:

[0017] By setting adjacent first and second planar reflection gratings in the spectrometer, light undergoes secondary dispersion through the two gratings. This eliminates the need for a large focal length focusing lens while maintaining spectrometer resolution, effectively reducing the overall size of the spectrometer, saving manufacturing costs, and facilitating miniaturization. Furthermore, the use of dual reflection gratings increases the diffraction angle, solving the problem of small diffraction angles for near-infrared light with high grating density, thus improving near-infrared diffraction efficiency. For example, while maintaining spectrometer resolution, improved diffraction efficiency can be achieved in a narrow spectral range of 1530-1560 nm. It should be noted that this also applies to any narrow band of infrared light. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a spectrometer based on a dual-plane reflection grating provided in an embodiment of this application;

[0020] Figure 2 This is a schematic diagram of another spectrometer based on a dual-plane reflection grating provided in the embodiments of this application.

[0021] The components include an entrance slit 100, a collimating lens 200, a first planar reflective grating 300, a second planar reflective grating 400, a focusing lens 500, a detector assembly 600, and a planar reflector 700.

[0022] The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0025] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of the present invention. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0026] The principle of a spectrometer is as follows: the light from the sample is focused and incident on the entrance slit of the spectrometer, and forms a parallel beam after passing through the collimating objective lens; the parallel beam is incident on the grating for spectral dispersion; the diffracted light after grating dispersion is incident on the focal plane at the exit point by the collimating objective lens; detectors such as CCD photocouplers and MPT photomultiplier tubes are located at the focal plane of the outgoing light; the detectors record the spectral signal to realize the detection of the spectral signal.

[0027] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a spectrometer based on a dual-plane reflection grating provided in an embodiment of this application. The spectrometer 000 based on the dual-plane reflection grating may include: an entrance slit 100, a collimating lens 200, a first plane reflection grating 300, a second plane reflection grating 400, a focusing lens 500, and a detector assembly 600.

[0028] The entrance slit 1000 in the spectrometer 000 based on a dual-plane reflection grating can be used to emit a light beam.

[0029] In the spectrometer 000 based on a dual-plane reflection grating, the collimating lens 200 can be located on the light-emitting side of the entrance slit 100, used to collimate the light beam and guide it to the first plane reflection grating 300. For example, the collimating lens 200 can be either an inexpensive spherical mirror or an off-axis parabolic mirror, its main function being to collimate the measured optical signal coupled into the spectrometer off-axis into a parallel beam.

[0030] In the spectrometer 000 based on a dual-plane reflection grating, the first plane reflection grating 300 can be used for beam splitting, and the split beam can be guided to the second plane reflection grating 400, which can perform secondary beam splitting.

[0031] In a spectrometer 000 based on a dual-plane reflection grating, the focusing lens 500 can be used to focus the beam after secondary dispersion and guide it to the photosensitive surface m of the detector assembly 600. For example, the focusing lens 500 can be a lens group or a concave mirror.

[0032] In this embodiment, by setting adjacent first planar reflection gratings 300 and second planar reflection gratings 400 in the spectrometer 000, the light undergoes secondary dispersion through the two planar reflection gratings. This ensures the spectrometer's resolution without requiring a focusing lens with a large focal length, effectively reducing the overall size of the spectrometer, saving manufacturing costs, and facilitating miniaturization. Furthermore, the use of dual reflection gratings increases the diffraction angle, solving the problem of small diffraction angles for near-infrared light with high grating density, thus improving the diffraction efficiency of near-infrared light. For example, while maintaining the spectrometer's resolution, it can improve the diffraction efficiency in a narrow spectral range of 1530-1560 nm. It should be noted that this also applies to any narrow band of infrared light.

[0033] In summary, this application provides a spectrometer based on a dual-plane reflection grating, which may include: an entrance slit, a collimating lens, a first plane reflection grating, a second plane reflection grating, a focusing lens, and a detector assembly. By setting adjacent first and second plane reflection gratings in the spectrometer, light undergoes secondary dispersion through the two gratings. This eliminates the need for a large focal length focusing lens while maintaining spectrometer resolution, effectively reducing the overall size of the spectrometer, saving manufacturing costs, and facilitating miniaturization. Furthermore, the use of a dual reflection grating increases the diffraction angle, solving the problem of small diffraction angles for near-infrared light with high grating line density, thus improving the diffraction efficiency of near-infrared light. For example, while maintaining spectrometer resolution, it can improve the diffraction efficiency in a narrow spectral range of 1530-1560 nm. It should be noted that this also applies to any narrow band of infrared light.

[0034] Optionally, the scribe line density of the first planar reflection grating 300 in the spectrometer 000 based on the dual-plane reflection grating can range from 900 / mm to 1400 / mm. The scribe line density of the second planar reflection grating 400 can also range from 900 / mm to 1400 / mm. Here, the incident angle of the first planar reflection grating 300 can be from 40 degrees to 50 degrees.

[0035] In the embodiments of this application, the scribe line density of the first planar reflection grating 300 in the spectrometer 000 based on the dual-plane reflection grating can be less than the scribe line density of the second planar reflection grating 400.

[0036] Optional, please refer to Figure 2 , Figure 2 This is a schematic diagram of another spectrometer based on a dual-plane reflection grating provided in this application embodiment. The spectrometer 000 based on the dual-plane reflection grating may further include a plane mirror 700 located on the light-emitting side of the focusing lens 500. This plane mirror 700 can be used to guide the beam focused by the focusing lens 500 to the photosensitive surface of the detector assembly 600. In this way, the plane mirror 700 can deflect the beam, facilitating a compact design of the spectrometer structure.

[0037] In this embodiment of the application, the detector assembly 600 in the spectrometer 000 based on a dual-plane reflection grating may include a detector 601 and a cylindrical lens 602. The cylindrical lens 602 may be located between the photosensitive surface m of the detector 601 and the reflective surface of the plane mirror 700, and the rear surface of the cylindrical lens 602 may be a plane. The rear surface of the cylindrical lens 602 may be arranged parallel to the window glass of the detector 601.

[0038] For example, the cylindrical lens 602 is made of ultraviolet fused silica material. With the above material setting, the cylindrical lens 602 has higher light transmittance, stronger refraction and ability to rotate plane polarized light, as well as a high damage threshold and scratch resistance. By adding a cylindrical lens in front of the linear array detector, and the cylindrical lens is made of ultraviolet fused silica material, it can not only be used for residual astigmatism correction and improve the energy utilization of the system, but also improve the durability of the overall structure and ensure the long-term stable operation of the system.

[0039] In summary, this application provides a spectrometer based on a dual-plane reflection grating, which may include: an entrance slit, a collimating lens, a first plane reflection grating, a second plane reflection grating, a focusing lens, and a detector assembly. By setting adjacent first and second plane reflection gratings in the spectrometer, light undergoes secondary dispersion through the two gratings. This eliminates the need for a large focal length focusing lens while maintaining spectrometer resolution, effectively reducing the overall size of the spectrometer, saving manufacturing costs, and facilitating miniaturization. Furthermore, the use of a dual reflection grating increases the diffraction angle, solving the problem of small diffraction angles for near-infrared light with high grating line density, thus improving the diffraction efficiency of near-infrared light. For example, while maintaining spectrometer resolution, it can improve the diffraction efficiency in a narrow spectral range of 1530-1560 nm. It should be noted that this also applies to any narrow band of infrared light.

[0040] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "multiple" refers to two or more unless otherwise expressly defined.

[0041] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A spectrometer based on a dual-plane reflection grating, characterized in that, include: An entrance slit, a collimating lens, a first planar reflective grating, a second planar reflective grating, a focusing lens, and a detector assembly; The entrance slit is used to emit a light beam; The collimating lens is located on the light-emitting side of the entrance slit and is used to collimate the light beam and guide it to the first planar reflective grating. The first planar reflective grating is used to split the beam and guide the split beam to the second planar reflective grating, which then splits the beam a second time. The focusing lens is used to focus the beam after secondary beam splitting and guide it to the photosensitive surface of the detector assembly.

2. The spectrometer based on a dual-plane reflection grating according to claim 1, characterized in that, The first planar reflective grating has a scribe line density ranging from 900 / mm to 1400 / mm; the second planar reflective grating has a scribe line density ranging from 900 / mm to 1400 / mm.

3. The spectrometer based on a dual-plane reflection grating according to claim 2, characterized in that, The scribe line density of the first planar reflective grating is less than that of the second planar reflective grating.

4. The spectrometer according to claim 1, characterized in that, The focusing lens is a lens group or a concave reflecting mirror.

5. The spectrometer based on a dual-plane reflection grating according to any one of claims 1-4, characterized in that, The spectrometer based on a dual-plane reflection grating further includes a plane mirror located on the light-emitting side of the focusing lens, the plane mirror being used to guide the light beam focused by the focusing lens to the photosensitive surface of the detector assembly.

6. The spectrometer based on a dual-plane reflection grating according to claim 5, characterized in that, The detector assembly includes a detector and a cylindrical lens. The cylindrical lens is located between the photosensitive surface of the detector and the planar reflector, and the rear surface of the cylindrical lens is flat and parallel to the window glass of the detector.

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